As was mentioned, depends on the amount of gain needed. If you need more gain, the SD-1 will be the ticket. Never tried an actual 808 but lots of pedals that were on the same gain level and sometimes i wanted a tad more..
I'd go with the TS808. I think it's a more natural sounding overdrive. I think it keeps the dynamics better and has a bigger overall sound. Side by side I think the SD-1 sounds a little more processed sounding.